ABSTRACT
C18-Silica used for Solid-Phase Extraction exhibits the same degree of adsorption of volatile hydrocarbons as compared to conventional Tenax adsorbent. The vapor pressure of the hydrocarbons and the velocity of the air sample through the sorbent are dominants of the preconcentration. Recovery of 80% for n-hexane and 98% for p-xylene at a concentration of 10 mg.m−3 was obtained at 10 ml.g−.min− velocity.
C18Bond Elut cartridges have been successfully used for quantitative determination of hydrocarbons as air pollutants by gas chromatography. The detection limit for p-xylene using preconcentration from 1 L air sample and a S/N ratio of 5 was 0.1 mg.m−3. After regeneration of C18Bond Elut cartridges by washing with acetonitrile and diethyl ether and drying at 85°C/15 min, their preconcentration potential remain acceptable upon reusing at least three times.